Exhaust pipe

ABSTRACT

An exhaust pipe comprises a pipe body formed therein with a silence chamber and an expansion chamber. A U-shaped gas inlet tube and a discharge tube are settled in the pipe body. The exhaust pipe facilitates smoothening waste gas discharge, generating appropriate exhaust back pressure and decreasing exhaust noise.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to an exhaust pipe through which a wastegas from a vehicle engine in operation is discharged.

2. Description of Related Art

A conventional exhaust pipe, as sown in FIG. 1, is a pipe body 10 insidedivided into a first expansion chamber 13, a second expansion chamber14, and a third expansion chamber 15 with two partitions 11. The secondexpansion chamber 14 is stuffed with a sound absorbing material 16. Agas inlet tube 17 passing through the first and second expansionchambers 13, 14 has a gas inlet 171 formed in a pipe wall of a first endof the pipe body 10 and a gas outlet 172 opened to the third expansionchamber 15. A gas outlet tube 18 passing through the second and thirdexpansion chambers 14, 15 has a gas inlet 182 opened to the firstexpansion chamber 13 and a gas outlet 183 jutting out the pipe body 10through the third expansion chamber 15. Besides, a connection tube 19settled in the second expansion chamber 14 connects the first expansionchamber 13 and the third expansion chamber 15.

The gas inlet 171 of the gas inlet tube 17 is connected to a maindischarge pipe of an engine, so that a waste gas of the engine entersthe pipe body 10 of the exhaust pipe through the gas inlet 171 and goesinto the third expansion chamber 15 by way of the gas outlet 172. Thenthe waste gas in the third expansion chamber 15 proceeds to the firstexpansion chamber 13 through the connection tube 19. Afterward, thewaste gas in the first expansion chamber 13 is discharged outward thepipe body 10 through the gas outlet tube 18.

When gushed to the third expansion chamber 15 though the gas outlet 172of the gas inlet tube 17 and when gushed to the first expansion chamber13 from the third expansion chamber 15 through the connection tube 19,the waste gas directly impacts inner walls 105, 106 and causes highimpact noises. Such gaseous impact also causes turbulent airflows in thefirst expansion chamber 13 and the third expansion chamber 15 and leadsto hindered exhaust and instable back pressure, resulting in depressedtorque output of the engine operating at low speed.

SUMMARY OF THE INVENTION

One primary objective of the present invention is to provide an exhaustpipe facilitating smooth waste gas discharge, appropriate exhaust backpressure for enhancing torque output of a vehicle engine operating atlow speed and decrease of exhaust noise.

To achieve these effects, the disclosed exhaust pipe comprises:

a closed pipe body, in which a partition defines at least one expansionchamber and at least one silence chamber that is filled with a soundabsorbing material, wherein the silence chamber has a capacity greaterthan a capacity of the expansion chamber and the partition is formedwith a plurality of vents for gaseous convection;

a U-shaped gas inlet tube, having a U-shaped body with a gas inlet and agas outlet at two ends thereof, wherein the U-shaped body is fixed inand axially parallel to the closed pipe body, a greater part of theU-shaped body being located in the silence chamber and wrapped by thesound absorbing material, the gas inlet being opened to a pipe wall ofthe closed pipe body while the gas outlet is located in the expansionchamber, and the part of the U-shaped body inside the silence chamberbeing formed with a plurality of noise elimination holes;

at least one discharge tube, having a tube body with a gas inlet and agas outlet at two ends thereof, wherein the tube body is fixed in andaxially parallel to the closed pipe body, a greater part of the tubebody being located in the silence chamber and wrapped by the soundabsorbing material, the gas inlet being located in the expansion chamberwhile the gas outlet is opened to the pipe wall of the closed pipe body,and the part of the tube body inside the silence chamber being formedwith a plurality of noise elimination holes.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention as well as a preferred mode of use, further objectives andadvantages thereof, will best be understood by reference to thefollowing detailed description of an illustrative embodiment when readin conjunction with the accompanying drawings, wherein:

FIG. 1 is a cross-sectional view of a conventional exhaust pipe;

FIG. 2 is a cross-sectional view of a first embodiment of the presentinvention;

FIG. 3 is another cross-sectional view of the first embodiment takenalong Line 3-3 of FIG. 2;

FIG. 4 is another cross-sectional view of the first embodiment takenalong Line 4-4 of FIG. 2;

FIG. 5 is a cross-sectional view of a second embodiment of the presentinvention; and

FIG. 6 is a cross-sectional view of a third embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

While some preferred embodiments are provided hereinafter forillustrating the concept of the present invention as described above, itis to be understood that the components in these drawings are made forbetter explanation and need not to be made in scale. Besides, in thefollowing description and the drawings, resemblances are indicated bythe same numerals.

Please refer to FIGS. 2, 3 and 4 for the cross-sectional views of afirst embodiment of the present invention. According to the presentembodiment, the exhaust pipe of the present invention has a closed pipebody 20, a U-shaped gas inlet tube 25 and a discharge tube 27.

The closed pipe body 20 has a partition 21 therein defining an expansionchamber 22 and a silence chamber 23. The silence chamber 23 has acapacity greater than that of the expansion chamber 22. The partition 21is formed with a plurality of vents 211 for gaseous convection.Furthermore, the silence chamber 23 is filled with a sound absorbingmaterial 24.

The U-shaped gas inlet tube 25 has a U-shaped body 251 with a gas inlet252 and a gas outlet 253 at two ends thereof. The U-shaped body 251 isfixed in the pipe body 20 and axially parallel to the pipe body 20. Agreater part of the U-shaped body 251 is located in the silence chamber23 and wrapped by the sound absorbing material 24. The gas inlet 252 isopened to a pipe wall of a first end 201 of the pipe body 20 while thegas outlet 253 is located in the expansion chamber 22. The part of theU-shaped body 251 inside the silence chamber 23 is formed with aplurality of noise elimination holes 26.

The discharge tube 27 has a tube body 271 with a gas inlet 272 and a gasoutlet 273 at two ends thereof. The tube body 271 is fixed in the pipebody 20 and axially parallel to the pipe body 20. A greater part of thetube body 271 is located in the silence chamber 23 and wrapped by thesound absorbing material 24. The gas inlet 273 is located in theexpansion chamber 22 while the gas outlet 273 is opened to the pipe wallof the first end 201 of the pipe body 20. The part of the tube body 271inside the silence chamber 23 is formed with a plurality of noiseelimination holes 28.

Please refer to FIG. 5 for the cross-sectional view of a secondembodiment of the present invention. According to the presentembodiment, the exhaust pipe of the present invention has a closed pipebody 20, a U-shaped gas inlet tube 25 and a discharge tube 30.

The closed pipe body 20 has a partition 21 therein defining an expansionchamber 22 and a silence chamber 23. The silence chamber 23 has acapacity greater than that of the expansion chamber 22. The partition 21is formed with a plurality of vents 211 for gaseous convection.Furthermore, the silence chamber 23 is filled with a sound absorbingmaterial 24.

The U-shaped gas inlet tube 25 has a U-shaped body 251 with a gas inlet252 and a gas outlet 253 at two ends thereof. The U-shaped body 251 isfixed in the pipe body 20 and axially parallel to the pipe body 20. Agreater part of the U-shaped body 251 is located in the silence chamber23 and wrapped by the sound absorbing material 24. The gas inlet 252 isopened to a pipe wall of a first end 201 of the pipe body 20 while thegas outlet 253 is located in the expansion chamber 22. The part of theU-shaped body 251 inside the silence chamber 23 is formed with aplurality of noise elimination holes 26.

The discharge tube 30 has a straight body 301 with a gas inlet 302formed on the straight body 301 and gas outlets 303 located at two endsof the straight body 301. The straight body 301 is fixed in the pipebody 20 and axially parallel to the pipe body 20. A greater part of thestraight body 301 is located in the silence chamber 23 and wrapped bythe sound absorbing material 24. The gas inlet 302 is located in theexpansion chamber 22 while the gas outlets 303 are opened to pipe wallsof the first end 201 and a second end 202 of the pipe body 20,respectively. The part of the straight body 301 inside the silencechamber 23 is formed with a plurality of noise elimination holes 28.

Please refer to FIG. 6 for the cross-sectional view of a thirdembodiment of the present invention. According to the presentembodiment, the exhaust pipe of the present invention has a closed pipebody 20, a U-shaped gas inlet tube 25 and a discharge tube 30.

The closed pipe body 20 has two partitions 21 therein defining anexpansion chamber 22 and two silence chambers 23. The expansion chamber22 is sandwiched between the two silence chambers 23. Each of thesilence chambers 23 has a capacity greater than that of the expansionchamber 22. The partition 21 is formed with a plurality of vents 211 forgaseous convection. Furthermore, the silence chambers 23 are each filledwith a sound absorbing material 24.

The U-shaped gas inlet tube 25 has a U-shaped body 251 with a gas inlet252 and a gas outlet 253 at two ends thereof. The U-shaped body 251 isfixed in the pipe body 20 and axially parallel to the pipe body 20. Agreater part of the U-shaped body 251 is located in the silence chamber23 and wrapped by the sound absorbing material 24. The gas inlet 252 isopened to a lateral wall 203 of the pipe body 20. The gas outlet 253 islocated in the expansion chamber 22. The part of the U-shaped body 251inside the silence chamber 23 is formed with a plurality of noiseelimination holes 26.

The discharge tube 30 has a straight body 301, a gas inlet 302 formed onthe straight body 301 and gas outlets 303 at two ends of the straightbody 301. The straight body 301 is fixed in the pipe body 20 and axiallyparallel to the pipe body 20. A greater part of the straight body 301 islocated in the silence chambers 23 and wrapped by the sound absorbingmaterials 24. The gas inlet 302 is located in the expansion chamber 22while the gas outlets 303 are opened to pipe walls of a first end 201and a second end 202 of the pipe body 20, respectively. The part of thestraight body 301 inside the silence chamber 23 is formed with aplurality of noise elimination holes 28.

According to the foregoing embodiments, a waste gas of an engine entersthe U-shaped body 251 through the gas inlet 252 of the U-shaped gasinlet tube 25 and is released to the expansion chamber 22 by way of thegas outlet 253 for decompression. Then the waste gas in the expansionchamber 22 enters the tube body 271 or 301 through the gas inlet 272 or302 of the discharge tube 27 or 30. At last, the waste gas is dischargedoutward the pipe body 20 through the gas outlet(s) 273 or 303.

The U-shaped gas inlet tube 25 leads the waste gas to flow smoothly inthe pipe body 20.

The U-shaped gas inlet tube 25 provides an extended path for the wastegas to flow in the pipe body 20 so that the noise elimination holes 26or 28 and the sound absorbing material 24 serve to significantly reduceexhaust noise of the exhaust pipe. In addition, the discharge tube 27 or30 also presents reduced exhaust noise in virtue of the noiseelimination holes 28 or 31 and the sound absorbing material(s) 24.

The U-shaped gas inlet tube 25 defines a U-shaped flow path so that theflowing waste gas generates a back pressure that facilitates enhancingtorque output of an engine operating at low speed. In cooperation withthe U-shaped discharge tube 27, the back pressure can be furtherincreased.

The vents 211 on the partition(s) 21 provide passageways communicatingthe waste gas in the silence chamber 23, 231, 232 and the expansionchamber 22 so as to prevent the silence chamber 23, 231, 232 or theexpansion chamber 22 from getting overpressed.

Since the waste gas receives process of expansion, decompression andnoise elimination in the expansion chamber 22 before entering thedischarge tube 27 or 30 through the U-shaped gas inlet tube 25, thedischarge tube 27 or 30 receives a reduced exhaust pressure, therebyallowing smoother and quieter exhaust. The expansion chamber 22 alsoprovides an appropriate pressure to the U-shaped gas inlet tube 25 tomodulate gaseous beck pressure in the U-shaped gas inlet tube 25.

The noise elimination holes 26 or 28 of the U-shaped gas inlet tube 25and the noise elimination holes 28 or 31 of the discharge tube 27, 30may be altered in amount, position, configuration, concentration,diameter and so on at manufacture so as to present different exhaustmagnitudes and even different acoustic frequencies of exhaust.

Although the particular embodiments of the invention have been describedin detail for purposes of illustration, it will be understood by one ofordinary skill in the art that numerous variations will be possible tothe disclosed embodiments without going outside the scope of theinvention as disclosed in the claims.

1. An exhaust pipe, comprising: a closed pipe body, in which a partitiondefines at least one expansion chamber and at least one silence chamberthat is filled with a sound absorbing material; a U-shaped gas inlettube, having a U-shaped body with a gas inlet and a gas outlet at twoends thereof, wherein the U-shaped body is fixed in and axially parallelto the closed tube, the gas inlet being opened to a pipe wall of thepipe body while the gas outlet is located in the expansion chamber, andthe U-shaped body inside the silence chamber being wrapped by the soundabsorbing material and formed with a plurality of noise eliminationholes; at least one discharge tube, having a tube body with a gas inletand a gas outlet at two ends thereof, wherein the tube body is fixed inand axially parallel to the closed tube, a greater part of the tube bodybeing located in the silence chamber and wrapped by the sound absorbingmaterial, the gas inlet being located in the expansion chamber while thegas outlet is opened to the pipe wall of the pipe body, and the part ofthe tube body inside the silence chamber being formed with a pluralityof noise elimination holes.
 2. The exhaust pipe of claim 1, wherein, thesilence chamber has a capacity greater than a capacity of the expansionchamber.
 3. The exhaust pipe of claim 1, wherein, the partition isformed with a plurality of vents for gaseous convection.
 4. The exhaustpipe of claim 1, wherein, the gas inlet of the U-shaped gas inlet tubeis opened to the pipe wall of a first end of the pipe body.
 5. Theexhaust pipe of claim 4, wherein, the tube body of the discharge tube isin a U shape.
 6. The exhaust pipe of claim 5, wherein, the gas outlet ofthe discharge tube is opened to the pipe wall of the first end of thepipe body.
 7. The exhaust pipe of claim 4, wherein, the tube body of thedischarge tube is in a straight shape.
 8. The exhaust pipe of claim 7,wherein, the gas inlet of the discharge tube is located in the expansionchamber and two ends of the tube body is formed with a respective gasoutlet in which the gas outlets are opened to the pipe wall of the firstend and a pipe wall of a second end of the pipe body, respectively. 9.The exhaust pipe of claim 7, wherein, another partition in the pipe bodydefines another silence chamber that is also filled with a soundabsorbing material, in which the expansion chamber is sandwiched betweenthe two silence chambers.
 10. The exhaust pipe of claim 9, wherein, thepartition is formed with a plurality of vents for gaseous convection.11. The exhaust pipe of claim 10, wherein, the gas inlet of the U-shapedair inlet tube is opened to a lateral wall of the pipe body.